The present disclosure relates to a power conversion device, and particularly, to a power conversion device for charging each of a high voltage battery and a low voltage battery.
Power conversion devices are provided in plug-in hybrid electric vehicles (PHEVs) or general battery electric vehicles (BEVs). Such a power conversion device may be system receiving a commercial alternating current (AC) power from the outside to charge a high voltage battery for driving electric vehicles. The high voltage battery may be charged through an on board charger (OBC) mounted within electric vehicles.
A power conversion device converts a commercial AC power into a direct current (DC) power through full-wave rectification to adjust a power factor of the converted DC power by using an active filter. Then, the DC power of which the power factor is adjusted is converted into high frequency AC power by using an inverter. Thereafter, the high frequency AC power is converted into a DC power via a transformer to charge the high voltage battery for supplying a power required for driving electric vehicles.
The power conversion device includes a high-speed switching circuit that switches an inputted DC voltage at a high speed to convert the switched DC voltage into a high frequency AC power, thereby outputting the converted high frequency AC power.
In electric vehicles, a low voltage battery supplying a power to a power system for electric device is charged by reducing an output of a high voltage battery supplying a power for driving vehicles through a DC-DC converter circuit. The high efficiency DC-DC converter circuit includes a high-speed switching circuit that switches an inputted DC voltage at a high speed to convert the DC voltage into a high frequency AC power to output the converted high frequency AC power.
Therefore, a charger for charging the high voltage battery and a charger for charging the low voltage battery are mounted within the electric vehicle.
FIG. 1 is a circuit diagram of a power conversion device according to a related art.
Referring to FIG. 1, a power conversion device according to the related art includes an input unit 11, a first input switching unit 12, a first transformation unit 13, and a first output rectification unit 14. a first output filter 15, a high voltage battery 16, an input filter 21, a second input switching unit 22, a second transformation unit 23, a second output rectification unit 24, a second output filter 25, and a low voltage battery 26.
In an operation of the power conversion device, the commercial AC power is supplied into the input unit 11.
The input unit 11 rectifies a full-wave of the commercial AC power to convert the rectified commercial AC power into the DC power, thereby adjusting a power factor of the DC power to output the DC power of which the power factor is adjusted.
The first input switching unit 12 is constituted by a plurality of switches to convert the DC power outputted through the input unit 11 into an AC square wave.
The first transformation unit 13 is a transformer. The first transformation unit 13 transforms the power outputted through the first input switching unit 12.
The power outputted through the first transformation unit 13 is rectified through the first output rectification unit 14 and filtered through the first output filter 15. The high voltage battery 16 is charged with the filtered power.
Similarly, the input filter 21 filters the power outputted by an electrical discharge of the high voltage battery 16
As described above, the filtered power is supplied through the second input switching unit 22, the second transformation unit 23, the second output rectification unit 24, and the second output filter 25 to charge the low voltage battery 26 through the input filter 21.
The above-described power conversion apparatus according to a related art includes the first charger-input unit 11, the first input switching unit 12, the first transformation unit 13, the first output rectification unit 14, the first output filter 15, and the high voltage battery 16 for charging the high voltage battery, and the second charger-input filter 21, the second input switching unit 22, the second transformation unit 23, the second output rectification unit 24, the second output filter 25, and the low voltage battery 26 for charging the low voltage battery.
Here, in the power conversion device according to the related art, since the switching unit, the rectification unit, and the filter, which perform the same function, are provided in each of first and second chargers, the power conversion device mounted within the electric vehicle may increase in volume, and also the product may increase in price.